Different types of lamps exist, which include respective types of light-producing elements. Examples of such light-producing elements include incandescent light bulbs, fluorescent neon light tubes and halogen-tungsten bulbs.
Incandescent light bulbs are widely used and well known. Most of these incandescent light bulbs have a screw base allowing the light bulbs to be screwed into a complementary threaded socket, be it located on a room wall or ceiling, at the end of the elongated rod of a stand-lamp, or any other known position for light bulb sockets. Halogen-tungsten lamps have light bulbs which can similarly engage a complementary socket. Neon light tubes are operatively mounted to a socket called a ballast.
The known light-producing elements have a certain life span during which they can produce light, after which they must be dispatched and replaced with a new light-producing element. Therefore, the light-producing elements are removable from their respective sockets for allowing this replacement with a new light-producing element when they become burned out or otherwise unusable.
A problem associated with conventional lamps having a single light-producing element is that they must be unscrewed and removed if a light of another color than the one being emitted from the light bulb is desired.